It's is very common to see shrubs and small trees planted near sidewalks and driveways in Winnipeg, and each spring I see a great deal from the effects of piling snow on these smaller woody plants through the winter.
Some of that snow has granules of rock salt, and piling snow on these plants can seriously affect their health. Physical breakage from the weight of snow is the more visible and obvious effect, but the accumulated salt in the soil around these plants can cause long-term damage.
Salt accumulation increases the alkalinity of the soil, creating toxic effects in many susceptible plants. Yellowing of leaves in the early summer is the earliest sign, along with bright green leaf veins and sometimes brown blotches in between the veins.
And shrubs are not the only plants that suffer from salt intrusion -- dead grass is usually visible in the same areas where salt-laden snow has been piled. Arborists call this condition 'chlorosis'.
Broken branches can be pruned off, but it's more important to ameliorate the salted soil. Thoroughly hose down the shrubs and grass area where snow has accumulated to dilute the toxic effects of the salt. Fertilize the affected area with a tree-and-shrub garden fertilizer along with powdered or granular iron chelate.
In situations where shrubs have been badly damaged, I tell clients to remove them completely and re-think their planting options. Annuals may be a better choice. Perhaps you can add interlocking pavers adjacent to the sidewalk and driveway hard surfaces.
Michael Allen is a consulting urban forester and certified I.S.A. arborist and owner of Viburnum Tree Experts. He makes house and garden visits to assess tree and shrub problems. He can be contacted by calling 831-6503 or by e-mail at viburnumtrees@shaw.ca. You can also mail questions to Michael Allen, c/o Newsroom, Winnipeg Free Press, 1355 Mountain Ave., Winnipeg, MB, R2X 3B6. His website is
www.treeexperts.mb.ca
